MethodsThe study was divided into two phases. In the first phase, a random sample of 100 UK community optometrists were given an opportunity to select and grade eight digital slit-lamp images of anterior chamber angles using the original van Herick 4 point grading scale. The images were included in a clinical decision making study using computerised virtual case vignettes. In the second phase, hospital-based glaucoma specialist optometrists and glaucoma sub-specialist ophthalmologists graded the LACD of the right eye using a 7-point % grading scale in 57 consecutively presenting patients with suspect glaucoma. Inter-observer agreement was assessed using linearly weighted kappa (κw).

ResultsInter-observer agreement for community optometrists was moderate, with a mean κw for grading photographic images of 0.50 (95% confidence interval (CI) 0.43–0.57). Overall, ninety-two percent of observations were within one grade of the actual grade, although grading of narrow angles was associated with a 13% false negative error rate (based on a ≤ grade 2 threshold). For Phase 2 of the study, pairwise comparisons between optometrists and ophthalmologists showed that agreement was moderate to substantial (mean κw = 0.54–0.65) with a false negative rate of 1.9% (based on a ≤ 25% threshold). Grading accuracy of specialist optometrists and ophthalmologists were equivalent.

This is the peer reviewed version of the following article: Jindal A, Myint J, Edgar DF, Nolan WP & Lawrenson JG. Agreement among optometrists and ophthalmologists in estimating limbal anterior chamber depth using the van Herick method. Ophthalmic Physiol Opt 2015; 35: 179–185., which has been published in final form at http://dx.doi.org/10.1111/opo.12199 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.